For a fixed position of the probe (no coupling issues), the system calculates TFM images incrementally moving them by a few steps.
Transformice codes portable#
To simplify this task, Eddyfi Technologies has implemented an approach that follows the guidelines provided in standards for both the M2M Gekko® and Mantis™ portable flaw detectors.
Transformice codes code#
While the theoretical amplitude fidelity gives an approximate value for what the pixel size should be, standards clearly state that it must be experimentally measured on a test piece to be code compliant. All these parameters have an impact on the shape of the ultrasonic beam. The theoretical amplitude fidelity doesn’t consider other parameters such as material properties (attenuation), wedge definition, position of the grid relative to them, sampling frequency of the FMC, range, etc. Some TFM systems tend to calculate a theoretical amplitude fidelity based on an amplitude error that depends mainly on the central frequency and bandwidth of the transducer. Other standards require 2dB if amplitude is used for sizing and 4dB if sizing does not rely on the absolute amplitude of the signal. As the pixels get bigger, we can see that it is statistically possible to miss the maximum amplitude of the echo.ĪSME V states that amplitude fidelity shall be preserved to 2dB or less, and that the process applied to check this fidelity be included in the qualified procedure. With inspection speed being one of the challenges for TFM, particularly for units with a multiplexed architecture like 32x128 systems, it is important to find the right pixel size value and avoid oversampling the TFM image.Īs an example, the following images are TFM reconstructions with pixel sizes of λ/20, λ/5 and λ/3, respectively. The simple solution could be using a very fine TFM grid, but this would increase the computation time and seriously impact inspection productivity. If the TFM grid is too coarse an inspector could simply miss a small reflector, and if the operator uses amplitude-based techniques to size an indication, it may be underestimated. the pixels that compose the TFM image are small enough to properly measure the signal peak amplitude. Amplitude fidelity is a criterion that defines if the TFM image is properly discretized to preserve amplitude information, i.e.
0 kommentar(er)
